It is known to use in combination with an open topped burning chamber a device for directing a curtain of air along a predetermined path into and around the burning chamber to enhance the oxidation of the material burning therein and to reduce the amount of smoke produced. It is also known that in carrying out such a process an elongated nozzle assembly is useful in forming the desired curtain of air. For example, U.S. Pat. Nos. 3,773,000, issued Nov. 20, 1973 and 4,161,916, issued July 24, 1979, both to Applegate are directed to such a process, and apparatus. The thrust of these two patents is toward a specific nozzle structure in relation to the formation of the air curtain. Another pertinent patent is U.S. Pat. No. 3,899,984, issued Aug. 19, 1975 to Keyes, et al, which is directed to apparatus for carrying out the above-described method wherein multiple gas streams are employed instead of a single air curtain.
It has now been found that by adjusting the volume of air or other oxygen containing gas in its distribution across the air curtain itself, in combination with varying the interior volume of the burning chamber itself, an even greater efficiency in the burning process is achieved which results in both a reduced amount of produced smoke, and therefore a reduced opacity of emissions emanating from the burning process.